Changes in wool growth and the skin of Merino sheep following administration of cyclophosphamide

1974 ◽  
Vol 25 (6) ◽  
pp. 931 ◽  
Author(s):  
PJ Reis ◽  
RE Chapman
Keyword(s):  
Body Weight ◽  
Sweat Glands ◽  
Sebaceous Glands ◽  
Merino Sheep ◽  
Length Growth ◽  
Wool Growth ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Fibre Growth ◽  
Pre Treatment

Two Merino sheep were dosed orally, and two intravenously, with cyclophosphamide at the rate of 30 mg/kg body weight; the effects on wool growth were measured, and changes in the histology of skin and of wool follicles were studied. All sheep were readily defleeced following treatment. This effect was associated with a complete cessation of wool growth for a period of about 2 weeks with oral dosing and 2½ weeks with intravenous dosing. There was considerable variation in the time taken for new fibres to commence growth. Length growth rates during the period 28–36 days after dosing were consistently greater than pre-treatment rates. Post-treatment fibre diameters were variable compared with the pretreatment values. The extent to which the enhanced length growth after dosing would compensate for the loss of wool growth requires further investigation. Degenerative changes were observed in some wool follicles 1 hr after dosing, and proliferation of cells of the fibre and inner root sheath appeared to have ceased at 1 day. Fibre growth ceased prior to 4 days. Regeneration of most follicles commenced prior to 14 days after dosing, and regrowth of wool was apparent above the skin by 21 days. A small proportion of follicles was still inactive after 36 days. Changes were observed in the sebaceous and sweat glands, epidermis and dermis following dosing. Even 36 days after dosing, sebaceous glands were considerably enlarged and excess stratum corneum remained on the epidermis. Infiltration of the dermis by lymphocytes was observed as early as 1 hr after dosing and was intense by 28 days.

scholarly journals A Morphological and Histological Investigation of the Sinus Interdigitalis in Konya Merino Sheep

2021 ◽  
Vol 9 (8) ◽  
pp. 1509-1513
Author(s):  
Zekeriya Özüdoğru ◽  
Ramazan İlgün ◽  
Derviş Özdemir
Keyword(s):  
Hair Follicles ◽  
The Body ◽  
Sweat Glands ◽  
Histological Investigation ◽  
Sebaceous Glands ◽  
Morphometric Measurements ◽  
Merino Sheep ◽  
Inner Surface ◽  
Histological Characteristics ◽  
Neck Part

In the study, it was aimed to reveal the morphological, morphometric and histological characteristics of sinus interdigitalis found in the fore and hind feet of Konya merino sheep. For this purpose, the fore and hind feet of 10 Konya merino sheep, weighing between 44-79 kg, were used. Sinus interdigitalis were dissected out from the feet, and after morphometric measurements were made, morphological examinations were performed and photographed. The shape of the sinus interdigitalis, present in all the forefeet and hind feet, resembled a pipe consisting of neck and body. It was determined that the neck part was longer than the body at all feet. The inner surface of the gland was covered with hair, and there was more hair on the neck than on the body. The weight of the gland, body length and diameter, flexura, canal length and diameter were measured morphometrically. In the measurements made, it was determined that all the values of the forefeet were higher than the hind feet. In histological examination, it was found that the wall of the sinus interdigitalis consists of three layers: epidermis, dermis and fibrous capsule, and in the dermis, hair follicles, sebaceous glands, m. arrector pili and sweat glands were found.

Follicular determinants of the length and diameter of wool fibres. 2. Comparison of sheep differing in thyroid hormone status

1994 ◽  
Vol 45 (6) ◽  
pp. 1149 ◽  
Author(s):  
PI Hynd
Keyword(s):  
Thyroid Hormone ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Fibre Volume ◽  
Concomitant Change ◽  
Wool Growth ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Hormone Status ◽  
Dividing Cells

The thyroid hormone status of Corriedale sheep was manipulated in order to produce a change in the rate of fibre elongation (L) with no concomitant change in the diameter (D) of the fibres, to allow the follicular factors responsible for fibre L to be determined. Thyroidectomy resulted in a 60% decrease in wool growth per unit area of skin and a 40% decrease in the rate of fibre volume output, due largely to a decline in fibre L from 412 ,8m/day to 277 8m/day ( P < 0.0001) while fibre D was unchanged (23.9 8m v. 21.9 pm, P > 0-05). Elevation of plasma thyroxine levels to 250% of Control values had no significant effect on fibre L and D, but patch wool growth was increased ( P < 0.05). A high proportion (22.9%) of the follicles in the hypothyroid sheep was inactive in comparison to the low levels of inactivity in the control (1.2%) and hyperthyroid animals (0.1%). The rate of division of follicle bulb cells was depressed by hypothyroidism and increased by hyperthyroidism (P < 0.0001), but there was no effect of thyroid status on the size of the cortical cells released from the wool fibres. Hypothyroid sheep had slightly smaller follicle bulbs and dermal papillae than the control and hyperthyroid animals. The proportion of dividing cells entering the fibre cortex (estimated from cortical cell volume, rate of fibre volume growth and rate of cell division) was depressed by thyroidectomy suggesting that relatively more dividing cells entered the inner root sheath in the follicles of hypothyroid sheep. This is supported by the lower production ratio (ratio of area of fibre to area of fibre-plus-inner root sheath) of the hypothyroid sheep. It is concluded that the rate of fibre elongation is depressed in hypothyroid sheep as a result of both a reduction in the rate of division of cells in the follicle bulb and fewer of these dividing cells entering the fibre cortex. This mechanism allows rapid changes in the rate of fibre elongation to occur with little change in the size of the follicle bulb, and may account for a number of scenarios in which fibre length changes rapidly with no concomitant change in fibre diameter. Fibre diameter, on the other hand, appears to be closely related to the dimensions of the follicle bulb, and by association, to the rate of bulb cell production. Selection of sheep with small follicle bulbs and at the same time, high production ratios, may be means of increasing fibre length whilst maintaining low fibre diameter.

Localization of androgen receptors in human skin by immunohistochemistry: implications for the hormonal regulation of hair growth, sebaceous glands and sweat glands

1992 ◽  
Vol 133 (3) ◽  
pp. 467-NP ◽  
Author(s):  
R. Choudhry ◽  
M. B. Hodgins ◽  
T. H. Van der Kwast ◽  
A. O. Brinkmann ◽  
W. J. A. Boersma
Keyword(s):  
Human Skin ◽  
Hair Growth ◽  
Hair Follicles ◽  
Dermal Fibroblasts ◽  
Sweat Glands ◽  
Epidermal Keratinocytes ◽  
Target Cells ◽  
Sebaceous Glands ◽  
Root Sheath ◽  
Dermal Papillae

ABSTRACT A mouse monoclonal antibody against the N-terminal region of human androgen receptor (AR) was used to identify receptors by immunoperoxidase staining in frozen serial sections of skin from scalp, face, limb and genitalia of men and women aged 30–80 years. AR staining was restricted to cell nuclei. In sebaceous glands, AR were identified in basal and differentiating sebocytes. The percentage of receptor-positive basal sebocyte nuclei in the temple/forehead region was greater in males (65%) than in females (29%). AR staining was restricted to the cells of dermal papillae in anagen and telogen hair follicles. The percentage of dermal papillae containing AR was greater in males (58%) than in females (20%). The number of positively stained dermal papillae was lowest in female scalp skin. In 163 hair follicles sectioned, AR were absent from germinative matrix, outer root sheath (including the bulge region), inner root sheath, hair shaft and hair bulb, and from the capillaries present in some large dermal papillae. AR were present in pilosebaceous duct keratinocytes, suggesting that androgens may influence pilosebaceous duct keratinization. AR were also identified in interfollicular epidermal keratinocytes and dermal fibroblasts although, in both cell types, intensity and frequency of staining were greatest in genital skin. AR were identified in luminal epithelial cells of apocrine glands in genital skin and in certain cells of the secretory coils of eccrine sweat glands in all body sites. This study indicates that androgens regulate sebaceous gland and hair growth by acting upon two different types of target cells, the epithelial sebocytes of sebaceous glands and the mesenchymal cells of the hair follicle dermal papilla. AR staining in either cell type was not influenced by age in adults. The distribution of AR in human skin is consistent with the diverse effects of androgens on the structure and function of skin and its appendages. Journal of Endocrinology (1992) 133, 467–475

scholarly journals Effect of Intravenously Infused Dexamethasone on Collagen Metabolism in Skin of Merino Sheep

1979 ◽  
Vol 32 (6) ◽  
pp. 561
Author(s):  
Z Leish ◽  
BA Panaretto
Keyword(s):  
Body Weight ◽  
Intravenous Infusion ◽  
Collagen Metabolism ◽  
Merino Sheep ◽  
Wool Growth

The effects of an 8-day intravenous infusion of dexamethasone (7�6 mg kg-o.75 body weight) on collagen biosynthes's and wool growth in skin were examined in four Merino wethers.

scholarly journals A Relationship Between Sulphur Content of Wool and Wool Production by Merino Sheep

1967 ◽  
Vol 20 (1) ◽  
pp. 153 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks ◽  
OB Williams ◽  
AJ Williams
Keyword(s):  
Body Weight ◽  
Unit Area ◽  
Sulphur Content ◽  
Merino Sheep ◽  
Wool Production ◽  
Weight Index ◽  
Wool Growth ◽  
The Mean ◽  
Fleece Weight ◽  
The Relationship

The sulphur content of wool from 66 Peppin Merino wethers maintained together at pasture was measured in midside staples representing 49 weeks growth. The distribution of sulphur values was normal with a mean of 3�43 % and a range of 3�08-3�92 %. The sulphur content of the wool was inversely related to wool production among these sheep. There were no significant differences in the relationship when wool production was expressed as fleece weight index (F.W.I.), i.e. clean fleece weight/body weight (r = -0�48), as clean fleece weight (r = -0�42), or as wool growth per unit area of skin (r = - 0�37). The mean sulphur content of wool from sheep with the 10 highest values for F.W.I. was 3�27%, compared with a mean of 3 �55% sulphur for wool from sheep with the 10 lowest values for F.W.I.

N-[5-(4-Aminophenoxy)pentyl]phthalimide as a potential defleecing agent and its effect on wool growth

1980 ◽  
Vol 31 (4) ◽  
pp. 791
Author(s):  
DA Tunks ◽  
RDG Rigby ◽  
AM Downes ◽  
JA Lamberton ◽  
BA Panaretto ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Oral Dose ◽  
Feed Intake ◽  
Merino Sheep ◽  
Dose Rates ◽  
Wool Growth

Merino sheep, offered feed at two levels of intake, were given an oral dose of N-[5-(4-am1nophenoxy)- pentyllphthahmide at rates varying over 100-800 mg/kg body weight. Consistent defleecing was obtained at dose rates of 400 nig/kg and above. Feed intake did not Influence defleecing activity. lntravenous infusion of smaller amounts also allowed defleecing. Wool growth rate following dosing was not affected by a dose of 100 mg/kg, but doses of 200 and 400 mg/kg caused depressions of c. 15 and c. 70% respectively in the rate of wool growth in the 2 weeks after dosing. Blindness was observed In one sheep dosed at 400 mg/kg and In all sheep dosed at higher rates

Development of horns in merino sheep

1973 ◽  
Vol 21 (2) ◽  
pp. 153 ◽  
Author(s):  
AG Lyne ◽  
DE Hollis
Keyword(s):  
Hair Growth ◽  
Dermal Papilla ◽  
Hair Follicles ◽  
Sweat Glands ◽  
Sebaceous Glands ◽  
Merino Sheep ◽  
Female Foetus ◽  
Connective Tissue Sheath ◽  
Hair Formation ◽  
Dermal Papillae

Development of horns has been studied in 20 foetuses ranging in age from 55 to 144 days of gestation, and in 16 lambs, ranging in age from birth to 42 days. Samples from one adult have also been examined. An increase in the thickness of the epidermis appears to be the first indication of horn development, recognizable in a 75-day-old male foetus and in an 84-day-old female foetus. Primary hair follicles develop in the horn region and produce emerging hairs, but these follicles later degenerate and disappear. The sweat glands and sebaceous glands formed in association with these follicles also degenerate, usually after hair growth has ceased. Fusion of primary follicles is a common feature in the horn growing skin, particularly before hair formation; a common connective tissue sheath surrounds the lower parts of these fused follicles. No secondary follicles are formed in the horn region but some branching of the primary follicles has been observed. By 118 days of gestation the epidermis in the horn region becomes greatly thickened, with very long dermal papillae which are well vascularized and innervated. Medulla-like columns of cells are formed above each dermal papilla and these cells keratinize later than the cells between the columns. These medullary cells remain in contact with each other longer than do the other cells of the horny sheath. Numerous arteriovenous anastomoses, which develop at two levels in the dermis of the horn region, are in continuity with capillaries which enter the dermal papillae of the epidermis. An outgrowth of bone from the frontal region of the skull, which later becomes the bony core of the horn, is first seen in a male foetus at 118 days. Acetylcholinesterase-positive branched cells (Langerhans cells), present in the lower part of the thick epidermis of developing horns, are not discernible in fully formed horns.

Intake and long-term cysteine supplementation change wool characteristics of Romney sheep

2001 ◽  
Vol 52 (1) ◽  
pp. 29 ◽  
Author(s):  
R. G. Sherlock ◽  
P. M. Harris ◽  
J. Lee ◽  
G. A. Wickham ◽  
J. L. Woods ◽  
...  
Keyword(s):  
Growth Rate ◽  
Treatment Period ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Amino Acid Supplementation ◽  
Sulfur Concentration ◽  
Treatment Groups ◽  
Length Growth ◽  
Wool Growth ◽  
Pre Treatment

Sulfur amino acid supplementation increases wool production in sheep at low planes of nutrition but it is unclear whether there is any benefit of supplementation at planes of nutrition above maintenance and what implications this might have for wool quality characteristics. This experiment directly investigated the interaction between sulfur supplementation and plane of nutrition in terms of wool growth and fibre characteristics. Twenty-four Romney ewes, acclimatised in individual metabolism units over a 7-week pre-treatment period, were allocated to 1 of 4 treatment groups based on a 22 factorial arrangement. Groups were low (L) or high (H) intake (0.8 or 1.3 maintenance, respectively) with continuous intravenous infusion of either saline (–Cys) or cysteine (+Cys, 2 g/day). During the 3-month treatment period, measurements were obtained for liveweight, plasma cysteine concentration, wool sulfur concentration and output, clean wool growth, mean fibre diameter (MFD), length growth rate (LGR), colour, loose wool bulk, handle, and crimp frequency and character. Clean wool growth response (P < 0.05) to cysteine supplementation was greater for the L sheep (6.06 v. 4.31 g/100 cm2) than the H sheep (7.20 v. 6.13 g/100 cm2). The response to supplementation in LGR (P < 0.01) was similar in both H (14%) and L (20%) sheep. There was no response in MFD due to sulfur supplementation, although fibre diameter measurements made along the fibres suggest that there was a response in L but not H sheep (P < 0.1). Wool sulfur concentration and output increased as a result of cysteine supplementation but concentration increased more in L (30.6 v. 24.5 mg S/g; P < 0.01) than in H sheep (28.4 v. 26.2 mg S/g). Qualitative electrophoresis analyses suggested that the increase in wool sulfur was achieved primarily by an increase in ultra-high-sulfur proteins. Crimp frequency and character were both significantly (P < 0.01) enhanced by cysteine supplementation. It is concluded that cysteine supplementation, at feed intakes that commonly occur in the commercial situation, can produce a useful increase in wool growth. This growth increase is primarily accomplished by increasing length growth rate rather than fibre diameter, which should also improve the value of the wool fibre produced.

Effects of experimentally produced local subdermal temperature changes on skin temperature and wool growth in the sheep

1970 ◽  
Vol 74 (1) ◽  
pp. 83-90 ◽  
Author(s):  
A. G. Lyne ◽  
M. Jolly ◽  
D. E. Hollis
Keyword(s):  
Growth Rate ◽  
Fibre Diameter ◽  
Slight Reduction ◽  
Environmental Disturbances ◽  
Temperature Changes ◽  
Merino Sheep ◽  
Cooling Period ◽  
Length Growth ◽  
Wool Growth ◽  
Change In Mean

SUMMARYA heat-exchange chamber made of perspex was inserted beneath the skin of a Merino sheep. By passing water at predetermined temperatures through the chamber, the normal subdermal temperature of 37°C was raised approximately 4°C for 4 days, then lowered approximately 5°C for 4 days.In response to heating, the animal's temperature regulating mechanism was able to maintain a fairly constant subdermal temperature. However, it was unable to maintain as constant a subdermal temperature in response to cooling. There was, during the cooling period, an obvious nervous response to environmental disturbances manifested by sudden transient decreases in subdermal temperature over the chamber.During the cooling period there was a decrease of 12% in mean length growth rate of wool over the chamber but mean fibre diameter was unchanged. Heating produced a small decrease in mean fibre diameter, but no change in mean length growth rate. Heating appeared to produce a slight reduction in pigmentation of some fibres but neither heating nor cooling produced demonstrable changes in crimping.

The response of skin and wool growth to local subdermal temperature changes in a sheep

1970 ◽  
Vol 75 (3) ◽  
pp. 501-515 ◽  
Author(s):  
M. Jolly ◽  
A. G. Lyne
Keyword(s):  
Growth Rate ◽  
Marked Reduction ◽  
Fibre Diameter ◽  
Progressive Decrease ◽  
Epidermal Thickness ◽  
Sebaceous Glands ◽  
Temperature Changes ◽  
Length Growth ◽  
Heating And Cooling ◽  
Wool Growth

SUMMARYHeat-exchange chambers, one for heating and one for cooling, were surgically embedded beneath the skin of a sheep. The intensity of heating and cooling was progressively increased, producing average subdermal temperatures up to 50·3 °C over one chamber and down to 21·0 °C over the other. The normal subdermal temperature was 37·7 °C.Moderate heating produced a small increase in the length growth rate of wool over the hot chamber. Higher temperatures caused a marked reduction and with still further heating there was almost complete cessation of wool growth.In contrast to heating, cooling always caused a suppression of wool growth which became more pronounced as the degree of cooling was intensified. The length growth rate decreased to half of normal at one stage but it never ceased.There was evidence of a slight but progressive decrease in fibre diameter with increasing subdermal temperatures up to 45 °C but at a temperature of 48 °C many of the fibres exhibited a marked thickening. Cooling the skin had little effect on fibre diameter. Pigmentation of the fibres was unchanged throughout the whole range of temperatures used and there was no evidence of change in crimping of the fibres.Heating in the range 45–50 °C produced an increase in epidermal thickness. Sweat and sebaceous glands, and erector muscles appeared unchanged after heating or cooling but innervation of the skin appeared to be reduced by extreme heating.The skin and wool growth over a dummy chamber were normal and similar in all respects to that in other control areas.

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